Hi Greg,
On Fri, Feb 16, 2018 at 7:44 PM, Greg KH <greg@xxxxxxxxx> wrote:
> On Thu, Feb 15, 2018 at 01:02:27PM +0100, Ulrich Hecht wrote:
>> When the TTY buffers fill up to the configured maximum, a system lockup
>> occurs:
>>
>> [ 598.820128] INFO: rcu_preempt detected stalls on CPUs/tasks:
>> [ 598.825796] 0-...!: (1 GPs behind) idle=5a6/2/0 softirq=1974/1974 fqs=1
>> [ 598.832577] (detected by 3, t=62517 jiffies, g=296, c=295, q=126)
>> [ 598.838755] Task dump for CPU 0:
>> [ 598.841977] swapper/0 R running task 0 0 0 0x00000022
>> [ 598.849023] Call trace:
>> [ 598.851476] __switch_to+0x98/0xb0
>> [ 598.854870] (null)
>>
>> This can be prevented by doing a dummy read of the RX data register.
>>
>> This issue affects both HSCIF and SCIF ports. Reported for R-Car H3 ES2.0;
>> reproduced and fixed on H3 ES1.1. Probably affects other R-Car platforms
>> as well.
>>
>> Reported-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
>> Signed-off-by: Ulrich Hecht <ulrich.hecht+renesas@xxxxxxxxx>
>
> Should this go to older kernel versions as well?
> If so, how far back?
This code path dates back to full-history-linux commit 2898a0e08c6ffb63
("[PATCH] SH Merge") in 2.6.2, back in 2004.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
